The ability to reduce the surface tension of water is of great importance in waterborne coatings, inks, adhesives, and agricultural formulations because decreased surface tension translates into enhanced substrate wetting in actual formulations. Surface tension reduction in water-based systems is generally achieved through the addition of surfactants. Performance attributes resulting from the addition of surfactants include enhanced surface coverage, fewer defects, and more uniform distribution. Equilibrium surface tension performance is important when the system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Examples of such applications are spraying of coatings or agricultural formulations, and high speed gravure or ink-jet printing. Dynamic surface tension is a measure of the ability of a surfactant to reduce surface tension and provide wetting under such high speed application conditions.
Traditional nonionic surfactants such as alkylphenol or alcohol ethoxylates, and ethylene oxide (EO) propylene oxide (PO) copolymers have excellent equilibrium surface tension performance, but are generally characterized as having poor dynamic surface tension reduction. In contrast, certain anionic surfactants such as sodium dialkyl sulfosuccinates provide good dynamic results, but are very foamy and impart water sensitivity to the finished coating.
The importance of reducing equilibrium and dynamic surface tension in applications such as coatings, inks, and agricultural formulations is well-appreciated in the art. Low dynamic surface tension is particularly important in the application of waterborne coatings. An article by J. Schwartz, entitled "The Importance of Low Dynamic Surface Tension in Waterborne Coatings," in Journal of Coatings Technology, September 1992, vol. 64, pages 65-74, provides a discussion of surface tension properties in waterborne coatings. Equilibrium and dynamic surface tension are evaluated for several surface active agents. At a concentration of 0.1% in distilled water, the dynamic surface tension ranges from a low of about 32 to a high of 72 dynes per centimeter. It is pointed out that low dynamic surface tension is an important factor in achieving superior film formation in waterborne coatings. Dynamic coating application methods require surfactants with low dynamic surface tensions in order to prevent defects such as retraction, craters, and foam.
Efficient application of agricultural products is also highly dependent on the dynamic surface tension properties of the formulation. An article by W. Wirth, S. Storp, and W. Jacobsen, entitled "Mechanisms Controlling Leaf Retention of Agricultural Spray Solutions" in Pestic. Sci.,1991, vol. 33, pages 411-420, provides information on the relationship between the dynamic surface tension of agricultural formulations and the ability of these formulations to be retained on a leaf. These workers observed a good correlation between retention values and dynamic surface tension; i.e., more effective retention formulations exhibited low dynamic surface tension.
Low dynamic surface tension is also important in high-speed printing, as discussed in an article by S. W. Medina and M. N. Sutovich, entitled "Using Surfactants to Formulate VOC Compliant Waterbased Inks," in American Ink Maker, 1994, vol.72 (No.2), pages 32-38. The authors state that equilibrium surface tension (EST) is pertinent to ink systems at rest, but are not good indicators of performance in the dynamic, high speed printing environment under which the ink is used. Dynamic surface tension is reported as a more appropriate property. The dynamic measurement is an indicator of the ability of the surfactant to migrate to a newly created ink/substrate interface to provide wetting during high speed printing.
U.S. Pat. No. 5,098,478 (Krishnan, et al., 1992) discloses water-based ink compositions that have a dynamic surface tension of about 25 to 40 dynes/cm in order to reduce printability problems.
U.S. Pat. No. 5,562,762 (Mrvos, et al., 1996) discloses effective surfactants for jet inks. The inks, in which the surfactants are used, are reported to have a static surface tension of less than 40 dynes/cm and a dynamic surface tension of about 65 dynes/cm, and display cohesive ink placement during use.
A wide variety of substituted cyclic ureas are known. For example, Nomura et al., Ind. Eng. Chem. Res., 1987, vol. 26, pages 1056-1059, disclose an effective catalyst for making cyclic ureas from carbonylation of diamines. The cyclic ureas are reported to be useful in a variety of applications; for example, as intermediates for medicines and resins, and as chemotherapeutic agents, delignification reagents, and in cosmetics.
U.S. Pat. No. 3,876,657 (Aelony et al., 1975) discloses preparation of 1-substituted-2-imidazolidinones. This class of compounds is recognized to have utility as bactericides, central nervous system depressants, plant growth promoters, female fly sterilants, adhesives, textile treating agents, and as monomers for deriving polymers and copolymers.
Naumov et al (translated article published in Khimiya Geteotsikl. Soedin. 1973, vol. 1, pages 90-93) disclose the synthesis of N-acyl and N-alkyl-substituted ethyleneurea. These materials are reported to be useful as biologically active compounds and many find practical application in pesticides.
Reports of alkylated aminoalkyl cyclic ureas are few and there are no known reports of alkylated aminoalkyl ureas having utility as surface tension reducing agents in water. In fact, Kanetani, et al., in Nippon Kagaku Kaishi, 1983, No.1, pages 107-111 (Chemical Abstracts, abstract # 98:145450e), disclose the conversion of N-alkylated aminoethylimidazolidinones to the propane sulfonic acid derivatives in order to make useful surfactants.